1. Field of the Invention
The present invention relates to a method for preparing a dimethyl dipropargylmalonate polymer, and particularly, to a method for preparing dimethyl dipropargylmalonate polymer containing six-membered ring structure from cyclopolymerization by using supercritical or sub-critical carbon dioxide as a solvent with transition metal chloride catalysts.
2. Description of the Background Art
In a polymer synthesis such as poly[bis(N-carbazoyl)-n-hexyl dipropargylmalonate], poly[bis(fluoroalkyl)dipropargylmalonate], poly(diethyl dipropargylmalonate), and poly(dipropargylsilanes), solvent such as chlorobenzene, benzene, toluene, tetrahydrofuran, dichloromethane, 1,2-dichloroethane, chloroform, and nitrobenzene is generally used, and transition metal chloride such as MoCl5 is generally used as a catalyst to perform a cyclopolymerization (Macromolecules 1988, 21, 1991; Macromolecules 1990, 23, 3029; Macromolecules 1991, 24, 973; Macromolecules 1993, 26, 1191).
Even if the polymer has a bright application aspect because of excellent photoconductivity and electric conductivity, it has a problem that environment is seriously polluted by an organic solvent used in the polymerization and a problem that cyclopolymer having two structures simultaneously is generated (J. Am. Chem. Soc. 1994, 116, 2827).
Therefore, inventors of the present invention found that the aforementioned problems could be solved by using supercritical or sub-critical carbon dioxide instead of an organic solvent in a process for preparing dimethyl dipropargylmalonate.
Therefore, an object of the present invention is to provide a method for preparing dimethyl dipropargylmalonate polymer containing exclusively six-membered ring structure without five membered ring structure by using supercritical or sub-critical carbon dioxide having no toxicity, non-flammability and harmless to environment as a solvent, wherein a cleaner production processing is performed.
The foregoing and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings.